Numbering presses for numbering sheets of securities, or as the case may be a continuous web of securities, are known in the art. International Publications Nos. WO 2006/129245 A2 and WO 2007/060624 A1, both in the name of the present Applicant and incorporated herein by reference in their entirety, for instance disclose such numbering presses.
Varnishing of banknotes was and is especially carried out to increase the durability and life-cycle of banknotes put into circulation. Information about the varnishing of banknotes can for instance be found in the following papers:
[Buitelaar1999]:                Tom Buitelaar, De Nederlandsche Bank NV, Amsterdam, the        Netherlands, “Effects of Banknote varnishing”, Currency        Conference CSI, Sydney 1999;        
[deHeij2000]:                Hans A. M. de Heij, De Nederlandsche Bank NV, Amsterdam, the Netherlands, “The design methodology of Dutch banknotes”, IS&T/SPIE's 12th International Symposium on Electronic Imaging, Optical Security and Counterfeit Deterrence Techniques III, San José, Calif., USA (Jan. 27-28, 2000), Proceedings of SPIE vol. 3973, pp. 2-22;        
[Wettstein2000]:                Frank Wettstein, Cash Division, Swiss National Bank, Berne and Hubert Lieb, Environmental Unit, Swiss National Bank, Zurich, “Life cycle assessment (LCA) of Swiss banknotes”, Quarterly Bulletin 3/2000 of the Swiss National Bank, September 2000;        
[Buitelaar2003]:                Tom Buitelaar, De Nederlandsche Bank NV, Amsterdam, the Netherlands, “Circulation Fitness Management”, Banknote 2003 Conference, Washington D.C., Feb. 3, 2003;        
Further information about the varnishing of banknotes and like security documents might be found in European Patent Publications Nos. EP 0 256 170 A1, EP 1 932 678 A1 and International Publications Nos. WO 01/08899 A1, WO 02/094577 A1, and WO 2006/021856 A1.
Varnishing presses for varnishing sheets or a continuous web of securities are also known in the art. International Publications Nos. WO 02/051638 A1 and WO 2010/023598 A1, and European Patent Publication No. EP 0 976 555 A1 for instance disclose such varnishing presses.
WO 02/051638 A1 specifically discloses a stand-alone flexographic printing press which can be used for varnishing of banknotes comprising at least a first flexographic unit disposed above the path of the sheets for cooperation with a recto side of the sheets and at least a second flexographic unit disposed downstream of the first flexographic unit and below the path of the sheets for cooperation with a verso side of the sheets. According to WO 02/051638 A1, the two flexographic units are separated by at least two intermediate cylinders and the second flexographic unit is offset in height with respect to the first flexographic unit.
EP 0 976 555 A1 specifically discloses a sheet-fed coating system consisting of multiple coating units disposed one after the other along the path of the sheets, the coating units being located both above and below the path of the sheets. According to EP 0 976 555 A1, such coating system can be coupled directly after a conventional offset printing group or combined with additional offset printing units. There is however no disclosure or suggestion in this document regarding the coupling of the coating system to a numbering group.
All of the configurations envisaged in EP 0 976 555 A1 share a generally similar configuration with multiple printing or coating towers disposed one after the other along the path of the sheets, which configuration is similar to that of conventional printing presses used for non-security applications and requires a rather considerable footprint. More precisely, all these configurations make use of a series of transfer cylinders against the circumference of which the recto and verso sides of the sheets are alternately brought into contact, which solution thus necessitates intermediate drying of the sheets after each printing operation, before the sheets are transferred to the downstream located transfer cylinder. Such solution is inadequate for the application of oxidative solvent-based inks as drying times are too short with such configurations for the oxidative solvent-based inks to be dried before transfer of the sheet to the downstream located transfer cylinder.